If you haven't tried pizza on the ceramic grill, you need to. Add a wood chunk for smoke flavor and it's almost as good as wood fired pizza from a brick oven.
Simply, a small pizza fits a big tray but vise versa, not so much. With a 16" diameter, the pizza tray can handle virtually any pizza going to/from the grill. It makes a great serving tray too, going from kitchen to den. The tray is 18 ga. aluminum with a soft couple style (gentle sloping) rim.